You can bet your hat that this was a very different type of (re-inforced) concrete than what we are using to build houses these days. We use yet other kinds of concrete for tunnels or underwater. Just like the Romans used different building materials.
Both us and the Romans are and were building lots of different things for lots of different purposes with lots of different properties and trade-offs.
Some of the earliest re-inforced concrete was used to make better flowerpots. https://en.wikipedia.org/wiki/Reinforced_concrete#History
You can bet your hat that this was a very different type of (re-inforced) concrete than what we are using to build houses these days. We use yet other kinds of concrete for tunnels or underwater. Just like the Romans used different building materials.